Enzyme linked immuno mass spectrometric assay (ELIMSA)

Area of Science:

• Biochemistry
• Analytical Chemistry
• Biotechnology

Background:

• Enzyme Linked Immunosorbent Assay (ELISA) relies on reporter enzymes like horseradish peroxidase (HRP) or alkaline phosphatase (AP) producing detectable signals.
• Current ELISA methods often yield colored, fluorescent, or luminescent products, limiting sensitivity and flexibility.
• Mass spectrometry (MS) offers high sensitivity and flexibility for detecting and quantifying molecules.

Purpose of the Study:

• To introduce Enzyme Linked Immuno Mass Spectrometric Assay (ELIMSA), a novel technology combining ELISA and MS.
• To leverage the enzymatic amplification of ELISA with the sensitivity and flexibility of MS for enhanced molecular detection.
• To enable the sensitive detection and quantification of low-abundance analytes relevant to medicine, industry, and environmental monitoring.

Main Methods:

• ELIMSA utilizes reporter enzymes (HRP or AP) covalently attached to detection probes (e.g., antibodies) to bind target analytes.
• These enzymes catalyze the production of small molecules that ionize efficiently for MS detection.
• Combines ELISA principles with sensitive liquid chromatography (LC), electrospray ionization (ESI), and tandem mass spectrometry (MS/MS).

Main Results:

• ELIMSA achieves high signal-to-noise ratios for MS detection of enzyme-catalyzed products.
• Demonstrates absolute sensitivity down to attomolar levels for analytes like prostate-specific antigen (PSA).
• Offers comparable or superior sensitivity to traditional methods like radioimmunoassays and electrochemical detectors, using existing equipment.

Conclusions:

• ELIMSA provides a sensitive and flexible platform for quantifying immunological assays, particularly for low-abundance proteins.
• The method enables the detection and quantification of numerous molecules across a wide range of biologically important concentrations without radiolabels.
• ELIMSA variants are suitable for diverse applications in medicine, industry, nutrition, and environmental science, utilizing readily available reagents and instruments.